SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function histogram (children 2)
     ExpressionList (children 1)
      Identifier num
     ExpressionList (children 1)
      Literal UInt64_2
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier histogram
